Basic Information The Basic Information window is where you set the spatial type, the temporal type, which budgets are desired, the stress packages included in the model, global parameters for rewetting cells, and whether or not you would like to save model results. You do this by manipulating the various check boxes and option buttons. The Spatial Type frame, where you choose between a quasi-three-dimensional or fully three-dimensional model, deserves special consideration. In a fully three-dimensional model, the tops of a cell in one layer contacts the bottom of the cell in layer above it. If you select the Fully Three Dimensional option button, Graphic Groundwater will assume that this condition is true. The Top Elevation command will not be enabled in the Overlays menu for all layers below layer 1. Instead, Graphic Groundwater will set the top elevation of a cell equal to the bottom elevation of the cell in the layer above it. In addition, if you choose to have Graphic Groundwater calculate vertical leakance by checking the Calculate Vertical Leakance check box, the Vertical Leakance command is not enabled in the Overlays menu. Under fully three-dimensional conditions, the determination of vertical leakance, a required input property in MODFLOW, is based on a simple equation. Graphic Groundwater will determine vertical leakance from a vertical conductivity you set for each cell in a layer. This simplifies model development. Graphic Groundwater will not save results unless the Save Results check box is indicated. Graphic Groundwater files that include results can be extremely large. Consult McDonald and others (1991) for the proper application of the wetting capability (conversion of no flow (inactive) cells to active cells during model execution).